Stress transfer of reinforced concrete beam strengthened with near-surface mounted prestressed CFRP strips
Su Peng , Li Heng , Chou Jiaxuan , Peng Hui
DOI:10.11835/j.issn.1674-4764.2017.01.010
Received March 04, 2016,Revised , Accepted , Available online July 04, 2017
Volume ,2017,Pages 68-76
- Abstract
Due to the advantages of making full use of high strength of FRP and saving the cost of premature anchorages for prestressed FRP, the technique of strengthening with prestressed near-surface mounted (NSM) FRP was considered as a potential technique for strengthening of reinforced concrete structures. The bond behavior of the NSM CFRP strip in the stress transfer length after releasing the prestress was studied. Based on the bond slip constitutive relationship obtained from experimental research, the differential equation of the bond stress at the NSM FRP-concrete interface was established. Then the analytical solution of the differential equation was acquired according to the boundary conditions, and the equations of distribution of the bond stress at the bonded interface and the tensile stress of CFRP were presented. The theoretical results were in good agreement with the test results, which indicated that the equations could be used to predict the distribution of bond stress at the NSM FRP-concrete interface after prestressing force release. Moreover, the maximum allowable pre-stress was obtained by considering no debonding at the bonded joint to be induced due to pre-tension release.